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Container-based sanitation (CBS) refers to a sanitation system where toilets collect human excreta in sealable, removable containers (also called cartridges) that are transported to treatment facilities. CBS involves a commercial service which provides toilets and delivers empty containers when picking up full ones. The service transports and safely disposes of or reuses collected excreta.

A key benefit of CBS systems is relative low-cost. In addition, the process assures there is no human contact with excreta. Feces can be contained, carried, transported and emptied into treatment facilities without exposing humans to pathogens.

Since 2010, CBS has typically been used in low-income settings where it is not feasible or appropriate to use or construct sewerage systems.[1] This includes densely-populated urban neighborhoods, informal settlements, areas with high water tables, or where there is risk of frequent flooding.

In the context of the United Nations’ Sustainable Development Goal 6 to "ensure sanitation for all by 2030", CBS systems have emerged as a viable, low-cost sanitation solution.[2] Rapidly growing urban areas, refugee camps and emergency situations lend themselves to CBS solutions.

Background

CBS systems emerged against the backdrop of a rising global population and rapidly growing urban areas. The pressure to achieve Sustainable Development Goal 6 – “to ensure availability and sustainable management of water and sanitation services for all” – is increasing.[2]

Current operators of CBS systems have developed different approaches. As of 2017, several CBS systems are being tested for scalability. With suitable development, support and effective partnerships, some believe CBS can be scaled up to provide more low-income urban populations with safe sanitation. Costs for containment, collection, transport and treatment of excreta are expected to be lower than the cost of sewers and water treatment plants.[2]

Overview

The latest version of SOIL's EkoLakay container-based toilet.

Overall system

CBS is usually provided as a commercial service (typically for a weekly or monthly fee for a 'household subscription') that provides toilets and regularly collects excreta. All infrastructure associated with a CBS system is typically situated above ground. Excreta-filled containers are sealed and transported by CBS service providers to a designated treatment or disposal site. Water usage is limited to the amount required for hand washing and anal cleansing.[3]

One of the main advantages of CBS is that it is a modular system. Each aspect of the system (from technology to business model) can be adapted to fit the context.

Like pay-per-use public toilets, household subscription CBS services enable customers to discontinue usage if they so choose. The advantage of low upfront cost is another similarity to public toilets. The capital required for installing some household toilets and sanitation systems can be prohibitive. CBS toilets can be installed with very little upfront cost.

The toilet

A CBS toilet typically requires no water and can often be moved quite easily. The removable container for excreta is routinely exchanged for an empty container when it is full. The toilet bowl often has a lid. Odor is eliminated by adding a dry cover material or using a biodegradable plastic film. The goal is to eliminate human contact with feces, reduce odor and avoid attracting insects.

In most cases, but not all, CBS systems require separation of urine and excrement. Therefore, a urine-diverting dry toilet (UDDT) is often used. UDDTs are simple and minimize the volume of waste in the excreta container. Diverted urine is often drained into the soil if the water table is low enough. It can also be stored long enough for pathogen die-off so it can be used as plant fertilizer.

Container transport

Containers vary in size from 5 liters to 208 liters, depending on the particular CBS system. After sealing, the containers are transported by CBS service providers to centralized facilities where the waste is removed and processed. Containers are then disinfected before being delivered to a customer again.

Treatment, disposal and reuse

Waste processing can take many different forms, from simple pathogen reduction to full resource recovery techniques. Resource recovery from human waste collected by a CBS system is comparatively easier to convert into energy, animal feed or soil amendments. There is far less liquid to remove and treat since toilet waste has not been mixed with water from other household tasks.

Differentiating CBS from other systems

The underlying principles of a CBS system can appear superficially similar to models of excreta management, which also contain excreta in-situ. These might be bucket toilets or pan latrines. Excreta is carried in open containers which are likely to be emptied before proper treatment. In India, the term, manual scavenging refers to emptying pit latrines.

The key distinction is that while a CBS system can include manual collection of containers, the containers or cartridges are sealed and the excreta is treated. Humans do not come into contact with waste throughout the entire service chain of containment, emptying, transportation, treatment and disposal or reuse. Proponents also note that users have more freedom of choice in that CBS toilets are portable and customers could choose another service provider.

Government approvals

CBS has gained official recognition in Kenya as a safe and cost-effective alternative to sewers and on-site sanitation systems. However, many regions have yet to take any official stance on CBS. Some CBS service providers are currently working together with local government partners to conduct World Health Organization Sanitation Safety Planning, which is a modular risk assessment process used to systematically understand and mitigate health-related hazards for each link of the sanitation chain.

The CBS Alliance was formed in November 2016 to share information on “best practices” and collaborate on building industry standards of safety.

Financial considerations

Families pay significantly less for a household subscription (that includes a toilet) compared to the cost of constructing a latrine or pour flush toilet.[1] For example, Ghana households of up to five users pay about 9 USD a month.[5]

For the public sector, CBS systems offer a cost-effective option. Low infrastructure investment relative to sewer-based sanitation systems make CBS systems attractive. Costs are also kept down because water and energy are not needed.

Although CBS systems have shown considerable potential for cost recovery through service fees and sales of final products, the need to continue experimenting and identifying the right elements for business models and public financing remain.

Humanitarian response

In 2017 at the Kakuma refugee camp in Kenya, the CBS system run by Sanivation was shown to be cheaper pit latrines, given the costs associated with installation and frequent de-sludging. Due to quick installation, minimal permanent infrastructure and relatively low costs, CBS proved to be a system that was easily shipped to new areas and quickly scaled to match refugee, emergency or disaster response needs.

In response to the earthquake that struck Port-au-Prince Haiti in January 2010, the non-profit organization SOIL mounted the first large-scale humanitarian response using CBS. SOIL constructed over 200 public CBS toilets in 32 camps for internally displaced people throughout the city. Over SOIL’s five-year humanitarian response program more than 20,000 people accessed CBS toilets. Over 700 metric tons of waste was converted into compost and sold to the agricultural sector.[6][7]

Types and examples

The basic concept of the CBS system is being applied by various organizations and businesses around the world, differentiated mainly by the types of toilet interface used, financing models, and reuse or disposal methods.

Clean Team

Clean Team is a social enterprise providing safe, affordable in-home CBS toilets for low-income families in Kumasi, Ghana.[2] It began operations in 2011 as a joint venture between Water and Sanitation for the Urban Poor (WSUP) and Unilever. Toilets are provided at no initial cost, with a weekly charge paid by customers for a ‘Swap & Go’ service to collect full sealed containers and replace them with clean, empty containers.[8] Clean Team transports the waste and ensures its safe disposal and treatment at a processing center owned by Kumasi Metropolitan Assembly.

Loowatt

Loowatt is an enterprise that develops safe, closed-loop CBS solutions. Loowatt toilets are waterless and linked to value-generating treatment systems. Loowatt works across global markets serving diverse users, including customers at events and festivals in the UK, and urban households in low-income markets. In 2017, Loowatt toilets were being tested in five countries.

Sanergy: Fresh Life Toilet

Sanergy is a social enterprise making safe sanitation accessible and affordable in Africa’s urban informal settlements where there are no sewer connections. Sanergy's approach to solving the sanitation crisis involves five key steps: building a network of CBS franchises offering affordable ‘Fresh Life Toilets’; supporting its operating partners with access to finance, training, and marketing; collecting the waste regularly and safely removing it from the community; converting the waste into valuable end products, such as organic fertilizer, insect-based animal feed, and renewable energy; and selling the end products to Kenyan farms. As of October 2017, Sanergy serves 50,000 people daily through a network of 1,300 facilities in Nairobi.

Sanitation First: GroSan Toilet

Sanitation First, a UK and India based non-profit organization, has developed a container-based system suitable for use in India that does not contravene the country's strict manual scavenging laws.[8] The toilet, which they call a "GroSan Toilet" has an interface based around that of a urine diverting dry toilet (UDDT). Within the toilet superstructures are two spaces: one for the UDDT toilet and another for anal cleansing with water. Underneath, containers separately receive the three types of excreta: feces, urine, and anal wash water. Once full, the containers are taken to a central treatment facility. The waste products are stored, treated and disposed of safely, generally as an agricultural compost. As of November 2017 some 5,000 people were daily using these kinds of toilets in the Union Territory of Puducherry and Cuddalore, in the Indian state of Tamil Nadu.

SOIL: EcoLakay Toilets

The non-profit organization Sustainable Organic Integrated Livelihoods (SOIL) was established in Haiti in 2006, providing affordable household CBS services in some of the world’s poorest communities. Feces collected in locally made, urine-diverting container ‘EkoLakay’ toilets are transported to a composting facility, where they are safely transformed into agricultural-grade compost. This compost is then sold for agricultural application, improving both the fertility and water-holding capacity of local soils. Revenue from monthly user fees and compost sales are used to cover a part of the ongoing service costs.[9]

Sanivation

Sanivation is a social enterprise based in Kenya that partners with institutions to turn feces into a sustainable fuel. Sanivation offers mobile or permanent models of their ‘Bluebox’ toilet: a locally built, urine-diverting, dry CBS toilet. This waste is processed using their proprietary treatment technology, which harnesses solar-thermal energy to safely treat the waste and transform it into charcoal briquettes for sale, creating a financially sustainable and replicable business model for sanitation services.

x-runner

x-runner is a social enterprise registered in Switzerland with its main headquarters in Peru. Operations began in early 2012, piloting a dry-toilet and waste collection system, as well as a treatment process. x-runner provides customer households with a portable dry toilet from Separett. In less than an hour, a toilet is installed in a user’s home and accumulated waste is collected on a weekly basis. The waste is then safely processed into compost by x-runner.
Households pay a monthly fee for the toilet rental and collection service. In the past six years, x-runner has been providing safe sanitation to hundreds of households in Lima, Peru.

Packaging toilet

A packaging toilet is a dry toilet which seals all the excreta from one bowel movement into its own package. It does not use water. The smell of exreta is sealed away from other users of the toilet.

The design goes back to 1936, where it was used in Buckminster Fuller's Dymaxion house.[10] That toilet used shrinkwrap plastic for packaging the waste. Other designs are currently marketed by various companies.[11]

Society and culture

Trivia

A packaging toilet may have been imagined for the movie The Martian (film). The protagonist gets the nutrients to grow potatoes by cutting open many sealed aluminum pouches, each holding the solid waste of other astronauts.[citation needed]